The main objectives of this study is to develop an experimental animal mode with the clinical and pathologic features of primary demyelinating optic neuritis. The adult animal sensitized with myelin will develop an acute retrobulbar optic neuritis with the clinical features of neuroretinitis. The juvenile animals in contrast will develop a chronic retrobulbar optic neuritis with clinical remissions and relapses. These animals will be injected intravenously with horse radish peroxidase and they will be sacrificed at various intervals to detect the alterations of blood-optic nerve barrier. To detect any changes in the exoplasmic transport the adult as well as juvenile animal with clinical signs of optic neuritis will receive tritiated leucine intravitreally. These animals will be sacrificed at different intervals to study the fast as well as slow component of axoplasmic flow. The lamina cribrosa region of the experimental animals with acute optic neuritis will be examined for deposits of immune complexes as well as for antibodies by the indirect immuno-fluorescent technique. The human surgical as well as autopsy material with the diagnosis of optic neuritis from the files of registry of ophthalmic pathology, AFIP will be reviewed and this material will be compared with the histo-pathologic features of experimental disease.